3

No...:
The most likely cause of this is a virus and needs to clear out of the GI tract. The most important thing to do is to keep your child well hydrated. If he is able to drink fluids (don't worry about solid foods at this time), then keep giving him liquids. Also take note of his urine output - if he is not urinating and looks dry, unable to take fluids, then take him to the nearest er for IV fluid.
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Start with 2 tablets:
Adults should take 4 mg (2 tablets) of Imodium (loperamide) to start, and then 2 mg (1 tablet) after each loose stool that follows. Do not take more than 16 mg (8 tablets) in a day. Effects should take place within 2 days so it might be a good idea to start taking it the day before your trip. If you don’t see improvement after two days or it gets worse see talk to your doctor.
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10

Safe to stop:
Imodium (loperamide) treats just the diarrhea itself, not what causes the diarrhea. After 4 days, not only is it safe to stop, it's probably recommended to stop to make sure that the underlying cause of the diarrhea has gotten better.
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